X87: [compiler] Introduce initial StrictEqualStub.

src/x87/code-stubs-x87.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 2907 matching lines @@
   if (equality) {
     StringHelper::GenerateFlatOneByteStringEquals(masm, left, right, tmp1,
                                                   tmp2);
   } else {
     StringHelper::GenerateCompareFlatOneByteStrings(masm, left, right, tmp1,
                                                     tmp2, tmp3);
   }
 
   // Handle more complex cases in runtime.
   __ bind(&runtime);
-  __ pop(tmp1);  // Return address.
-  __ push(left);
-  __ push(right);
-  __ push(tmp1);
   if (equality) {
-    __ TailCallRuntime(Runtime::kStringEquals);
+    {
+      FrameScope scope(masm, StackFrame::INTERNAL);
+      __ Push(left);
+      __ Push(right);
+      __ CallRuntime(Runtime::kStringEqual);
+    }
+    __ sub(eax, Immediate(masm->isolate()->factory()->true_value()));
+    __ Ret();
   } else {
+    __ pop(tmp1);  // Return address.
+    __ push(left);
+    __ push(right);
+    __ push(tmp1);
     __ TailCallRuntime(Runtime::kStringCompare);
   }
 
   __ bind(&miss);
   GenerateMiss(masm);
 }
 
 
 void CompareICStub::GenerateReceivers(MacroAssembler* masm) {
   DCHECK_EQ(CompareICState::RECEIVER, state());
@@ skipping 2646 matching lines @@
                            return_value_operand, NULL);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87